The degree of calcification as well as the structural changes of the elasti
c fibres in the ligamentum flavum in patients with degenerative lumbar spin
al stenosis were evaluated and the results were compared to those of patien
ts without spinal stenosis. In 21 patients (13 male, 8 female) with lumbar
spinal stenosis the ligamentum flavum was removed, histologically processed
and stained. The calcification, the elastic/collagenous fibre ratio as wel
l as the configuration of the fibres were evaluated with an image analyzing
computer. As a control group, 20 ligaments of 10 human corpses were proces
sed in the same way. The results were statistically analysed using the Mann
-Whitney-Wilcoxon test (alpha = 0.05) and the t-test (alpha = 0.05). Nearly
all the ligaments of patients with lumbar spinal stenosis were calcified (
average 0.17%, maximum 3.8%) and showed relevant fibrosis with decreased el
astic/collagenous fibre ratio. There was a significant correlation between
age and histological changes (P < 0.05). In the control group we only found
minimal calcification in 3 of 20 segments (average 0.015%). No relevant fi
brosis was found and the configuration of elastic fibres: showed no patholo
gic changes. The results of this study illustrate the important role of his
tological changes of the ligamentum flavum for the aetiology of lumbar spin
al stenosis.